方案一:Try...Catch(执行效率不高)
方案二:正则表达式(推荐)
a)
b)
public bool IsNumber(String strNumber)
{
Regex objNotNumberPattern=new Regex("[^0-9.-]");
Regex objTwoDotPattern=new Regex("[0-9]*[.][0-9]*[.][0-9]*");
Regex objTwoMinusPattern=new Regex("[0-9]*[-][0-9]*[-][0-9]*");
String strValidRealPattern="^([-]|[.]|[-.]|[0-9])[0-9]*[.]*[0-9]+$";
String strValidIntegerPattern="^([-]|[0-9])[0-9]*$";
Regex objNumberPattern =new Regex("(" + strValidRealPattern +")|(" + strValidIntegerPattern + ")");
return !objNotNumberPattern.IsMatch(strNumber) &&
!objTwoDotPattern.IsMatch(strNumber) &&
!objTwoMinusPattern.IsMatch(strNumber) &&
objNumberPattern.IsMatch(strNumber);
}
方案三:遍历
a)
b)
c)
方案四:改写vb的IsNumeric源代码(执行效率不高)
//-----------------
//StringType.IsHexOrOctValue(text1, ref num2))
internal static bool IsHexOrOctValue(string Value, ref long i64Value)
{
int num1;
int num2 = Value.Length;
while (num1 < num2)
{
char ch1 = Value[num1];
if (ch1 == '&')
{
ch1 = char.ToLower(Value[num1 + 1], CultureInfo.InvariantCulture);
string text1 = StringType.ToHalfwidthNumbers(Value.Substring(num1 + 2));
if (ch1 == 'h')
{
i64Value = Convert.ToInt64(text1, 0x10);
}
else if (ch1 == 'o')
{
i64Value = Convert.ToInt64(text1, 8);
}
else
{
throw new FormatException();
}
return true;
}
if ((ch1 != ' ') && (ch1 != '/u3000'))
{
return false;
}
num1++;
}
return false;
}
//----------------------------------------------------
// DoubleType.TryParse(text1, ref num1);
internal static bool TryParse(string Value, ref double Result)
{
bool flag1;
CultureInfo info1 = Utils.GetCultureInfo();
NumberFormatInfo info3 = info1.NumberFormat;
NumberFormatInfo info2 = DecimalType.GetNormalizedNumberFormat(info3);
Value = StringType.ToHalfwidthNumbers(Value, info1);
if (info3 == info2)
{
return double.TryParse(Value, NumberStyles.Any, info2, out Result);
}
try
{
Result = double.Parse(Value, NumberStyles.Any, info2);
flag1 = true;
}
catch (FormatException)
{
flag1 = double.TryParse(Value, NumberStyles.Any, info3, out Result);
}
catch (Exception)
{
flag1 = false;
}
return flag1;
}
方案五:直接引用vb运行库(执行效率不高)
方法:首先需要添加Visualbasic.runtime的引用
代码中Using Microsoft.visualbasic;
程序中用Information.isnumeric("ddddd");
以上就是C#判断一个String是否为数字类型的全部内容,推荐大家使用正则表达式的方法,比较简单且效率高。
新闻热点
疑难解答